Computation of accumulator matrix for Hough lines detection

image =	houghLines2dImg (inGreyImg2d)
image =	houghLines2dImg (inGreyImg2d,houghLinesImgParams)

Detailed Description

computes the accumulator matrix used by the Hough lines detector

This algorithm computes, from a grey levels 2d image, the accumulation matrix used to detect straight lines in the input image, using Hough transform.

See HoughLines2d for more information

Example of Python code :

Example imports

import PyIPSDK
import PyIPSDK.IPSDKIPLFeatureDetection as fd
import PyIPSDK.IPSDKIPLFiltering as filter

Code Example

    # opening of input image
    inImg = PyIPSDK.loadTiffImageFile(inputImgPath)
    
    # Initialize parameters for Hough lines accumulation matrix construction:
    # - step for rho = 1
    rhoStep = 2.0
    
    # - range of 15 evenly spaced orientations between pi/2 and 3.pi/4 radians
    thetaRange = PyIPSDK.createEvenlySpacedRange(math.pi/2, 3*math.pi/4, 15)
        
    # only accumulate pixels of input image with intensity greater than  210
    intensityThreshold = 210.0
    
    imgParams = PyIPSDK.createHoughLinesImgParams(
        rhoStep, thetaRange, intensityThreshold)


    # hough circle detection computation
    outImg = fd.houghLines2dImg(inImg, imgParams)

Example of C++ code :

Example informations

Header file

#include <IPSDKIPL/IPSDKIPLFeatureDetection/Processor/HoughLines2dImg/HoughLines2dImg.h>

Code Example

    ImageConstPtr pInImg = loadTiffImageFile(inImgPath);

    // Initialize parameters for Hough lines accumulation matrix construction:
    // - step for rho = 1
    const ipReal64 rhoStep = 1.0;

    // - range of 15 evenly spaced orientations between pi/2 and 3.pi/4 radians
    const EvenlySpacedRange& thetaRange = *createEvenlySpacedRange(
        M_PI / 2, 3 * M_PI / 4, 15);

    // only accumulate pixels of input image with intensity greater than  10
    const ipReal32 intensityThreshold = 10.0f;
    const HoughLinesImgParamsConstPtr pInHoughImgPrms = createHoughLinesImgParams(
        rhoStep, thetaRange, intensityThreshold);

    // launch Hough lines detection algorithm
    const ImageConstPtr pOutImg = houghLines2dImg(pInImg, pInHoughImgPrms);